How do I keep my puppy entertained when she's in a gated area while we aren't home?

I have a 3 month old Golden Retriever puppy and we have her gated in a small laundry room when it's bedtime or while we are away. And she gets bored and once we let her out she's extremely hyper. It looks as if she just sleeps the whole time she's penned up. Is there anything I can do or give her in that small space to keep her occupied? She's got a Kong but only licks the rim of it for a few minutes then loses interest. I know she will have lots of energy when I do finally let her out, but I don't want her to sleep all day and associate the pen with something negative. I want her to look forward to being in there when we aren't home or are asleep. It's also causing her to not want to come in after we go outside-she'll run from me when I try to get her to take her inside. So I want a way to keep her occupied while locked up as well as a way to teach her that the pen is not a bad place, but a fun one.